Adaptive wake-up scheduling under prs muting

ABSTRACT

Systems, methods, apparatuses, and computer-readable media for adaptive wake-up scheduling under PRS muting are disclosed. For example, a mobile device can receive a positioning reference signal measurement configuration for a muting pattern cycle having two or more time periods from a server. The mobile device then measures reference signals only during a subset of the two or more time periods of the muting pattern cycle based on the reference signal measurement configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. patent application Ser.No. 15/581,111, titled “Adaptive Wake-Up Scheduling Under PRS Muting,”filed Apr. 28, 2017, and having Attorney Docket No. 164780U1 (1022755),the entirety of which is hereby incorporated by reference.

BACKGROUND

Mobile devices are frequently equipped with sensors that can be used todetermine its location. For example, many mobile devices are equippedwith a Global Navigation Satellite System (“GNSS”) receiver, such as aGlobal Position System (“GPS”) receiver. Mobile devices may alsodetermine their locations using techniques to detect a distance to anearby cellular transmitter, such as using the observed time-differenceof arrival (“OTDOA”) technique, and provide such information to anetwork device, which calculates the mobile device's location andtransmits the location to the mobile device. To obtain high-qualitypositioning based on such cellular techniques, a mobile device mayobtain OTDOA measurements from a large number of nearby cellulartransmitters over a period of time, which can result in significantpower usage.

BRIEF SUMMARY

Various examples are described for adaptive wake-up scheduling under PRSmuting. One example method for receiving, by the mobile device, areference signal measurement configuration for the muting pattern cyclefrom a server; and measuring, by the mobile device, reference signalsonly during a subset of the two or more time periods of the mutingpattern cycle based on the reference signal measurement configuration.

An example device for measuring, by a mobile device, a plurality ofreference signals for positioning having a muting pattern cyclecomprising two or more time periods, the device includes anon-transitory computer-readable medium storing processor-executableinstructions; a processor in communication with the non-transitorycomputer-readable medium, the processor configured to execute theprocessor-executable program code to: receive a reference signalmeasurement configuration for a muting pattern cycle from a server; andmeasure reference signals only during a subset of the muting patterncycle based on the reference signal measurement configuration.

An example non-transitory computer-readable medium storingprocessor-executable instructions configured to cause a processor to:receive a reference signal measurement configuration for a mutingpattern cycle from a server; and measure reference signals only during asubset of the muting pattern cycle based on the reference signalmeasurement configuration.

An example apparatus for measuring a plurality of reference signals forpositioning having a muting pattern cycle comprising two or more timeperiods, the method comprising: means for receiving a reference signalmeasurement configuration for the muting pattern cycle from a server;and means for measuring reference signals only during a subset of themuting pattern cycle based on the reference signal measurementconfiguration.

These illustrative examples are mentioned not to limit or define thescope of this disclosure, but rather to provide examples to aidunderstanding thereof. Illustrative examples are discussed in theDetailed Description, which provides further description. Advantagesoffered by various examples may be further understood by examining thisspecification

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate one or more certain examples and,together with the description of the example, serve to explain theprinciples and implementations of the certain examples.

FIG. 1 shows an example environment for adaptive wake-up schedulingunder PRS muting;

FIGS. 2A-2B show example PRS muting cycles;

FIG. 3 shows an example system for adaptive wake-up scheduling under PRSmuting;

FIG. 4 shows an example mobile device adaptive wake-up scheduling underPRS muting;

FIGS. 5-6 show example methods for adaptive wake-up scheduling under PRSmuting; and

FIG. 7 shows an example wake-up schedule for adaptive wake-up schedulingunder PRS muting.

DETAILED DESCRIPTION

Examples are described herein in the context of adaptive wake-upscheduling under positioning reference signal (“PRS”) muting. Those ofordinary skill in the art will realize that the following description isillustrative only and is not intended to be in any way limiting.Reference will now be made in detail to implementations of examples asillustrated in the accompanying drawings. The same reference indicatorswill be used throughout the drawings and the following description torefer to the same or like items.

In the interest of clarity, not all of the routine features of theexamples described herein are shown and described. It will, of course,be appreciated that in the development of any such actualimplementation, numerous implementation-specific decisions must be madein order to achieve the developer's specific goals, such as compliancewith application- and business-related constraints, and that thesespecific goals will vary from one implementation to another and from onedeveloper to another.

In one illustrative example, a user of a mobile device turns on hermobile device. After the mobile device powers up, it begins to searchfor cellular transmitters in a cellular network that may be usable forproviding reference signals for determining the mobile device's locationusing OTDOA. In this example, the cellular transmitters are configuredto periodically transmit position reference signals (“PRS”), and eachcellular transmitter is assigned to one (or more) of a number ofavailable time periods within a repeating cycle. When a cellulartransmitter's time period occurs, it transmits its PRS; otherwise, itdoes not transmit a PRS, which is generally referred to as PRS “muting.”Each cycle may be referred to as a PRS muting cycle.

To use these position reference signals, the mobile device must activateits receiver at the appropriate times, based on which cellulartransmitter's PRS it is configured to receive. However, since at anygiven time, the mobile device may be within range of a number ofcellular transmitters, and because multiple PRSs are needed toaccurately determine its location, the mobile device must “wake up”during multiple time periods to receive PRS from different cellulartransmitters. However, because some receive PRS will be of betterquality than others, e.g., due to range to a transmitter, weather,multi-path effects, etc., the mobile device may need to select whichtime periods to “wake up” for, and which to “sleep” through.

The mobile device is configured to identify cellular transmitters to usefor location in two ways. In the first example, the mobile deviceaccesses its cell list to identify nearby cellular transmitters and toidentify time periods during which they transmit PRS. In this example,the mobile device identifies the ten nearby cellular transmitters havingthe best signal-to-noise ratio, and wakes up during the correspondingtime period of the PRS muting cycle and receives the PRS. Afterreceiving a PRS from each selected transmitter, it evaluates the qualityof the received PRS. If the quality is sufficiently high, the cellulartransmitter is marked as a “valid” PRS source; otherwise, the cellulartransmitter is indicated as having a “failed” PRS and may be struck fromthe list, or may be retried one or more times. The mobile phone maycontinue this process until a sufficient number of valid PRS sources areidentified, or until all nearby cells have been marked as valid orfailed.

In another example, rather than measuring the cells itself, the mobiledevice may send a request for assistance data to a PRS assistance systemfor information about PRS sources. The mobile device may then receiveassistance data identifying cells, the corresponding time periods in thePRS muting cycle, and respective quality of PRS from each identifiedcell.

The user then activates an application on her mobile device to find anearby coffee shop. The application, after launching, requests locationinformation from the mobile device's positioning system and indicates aneed for low precision location information, e.g., within 50 meters. Themobile device's positioning system receives the request and initiates alocation function to determine the mobile device's location. In thiscase, the mobile device first determines a number of PRS sourcesappropriate based on the application's location precision target. Basedon the low precision target, the mobile device determines that four PRSsources will be sufficient, and selects four PRS sources having highquality PRS reference signals. The mobile device then determines thecorresponding time periods within the PRS muting cycle and wakes up atthe appropriate times to receive the PRS. After receiving the PRSs, thepositioning system performs measurements on the received PRSs andprovides the measurements to a remote cellular network device, whichdetermines the mobile device's location and transmits the determinedlocation to the mobile device.

Later, the user witnesses a car accident and dials 911. The telephoneapplication detects the 911 call and transmits a request to the mobiledevice's positioning system for a location and indicates a need for thehighest possible precision location information. The positioning systemthen determines that as many PRS sources should be used as possible andselects all PRS sources that are marked “valid.” The mobile device thenwakes up at each time period corresponding to one (or more) of theselected PRS sources, or the mobile device simply wakes up for everytime period to receive all available PRS. The mobile device themperforms measurements on the received PRS information and provides themto a cellular network device, which again determines the mobile device'slocation and provides it to the mobile device, which then transmits thelocation to an E911 server.

This illustrative example is given to introduce the reader to thegeneral subject matter discussed herein and the disclosure is notlimited to this example. The following sections describe variousadditional non-limiting examples and examples of systems and methods foradaptive wake-up scheduling under PRS muting.

Referring now to FIG. 1, FIG. 1 shows an example environment 100 havinga mobile device 110 and a number of cellular transmitters 120 a, 120 b,120 c, 120 d, 120 e, 120 f, 120 g, 120 h, and 120 i, which may each alsobe referred to as a PRS source, at various locations in proximity to themobile device 110. As can be seen, the various cellular transmitters 120a-i are located at different distances and directions with respect tothe mobile device 110. Thus, when each cellular transmitter 120 a-itransmits at its PRS time period, the respective PRSs received by themobile device 110 will likely have different characteristics that mayaffect the quality of the PRS.

In the context of the example environment, each cellular transmitter 120a-i transmits a 3^(rd) Generation Partnership Project (“3GPP”) Long-TermEvolution (“LTE”) PRS, which comprises a pseudo-random quadrature phaseshift keying (“QPSK”) sequence. In another example, other PRS may beemployed and may not be specifically dedicated to providing a signal foruse in determining a mobile device's location. In this example, eachcellular transmitter's PRS will differ based on the transmitting cell'sidentity.

In this example, the mobile device 110 is configured to receive PRSbroadcast by the various cellular transmitters 120 a-i; however, basedon targets for position accuracy indicated by a software application,the mobile device 110 may only receive PRS from certain cells. Forexample, to reduce power consumption, the mobile device 110 may “sleep”through PRS broadcast from some cellular transmitters, while it may“wake up” in time to receive PRS broadcast from other cellulartransmitters. In general, the more PRS the mobile device 110 receives,the more accurately its position may be calculated. However, for manyapplications, highly-accurate position information is not required. Forexample, a mobile application that locates nearby restaurants may havemore relaxed targets for location accuracy than other applications, suchas emergency, e.g., E911, applications or even navigation applications.Thus, based on the accuracy needs of a requesting application, themobile device 110 may be able to sleep through more PRS broadcastsrather than expending battery power to wake up, receive, and process all(or even a significant majority) of PRS broadcasts.

Referring now to FIG. 2A, FIG. 2A illustrates an example of a PRS mutingcycle 200 which has multiple time periods 210. In this example, the PRSmuting cycle 200 has 8 time periods 210, numbered 1-8; however, othernumbers of time periods may be used, typically between 1 and 16 timeperiods per PRS muting cycle. In this example, each time period is 160milliseconds (“ms”), resulting in a PRS muting cycle with a period of1280 ms. Other time periods may be employed instead, including 320 ms,640 ms, and 1280 ms in different examples. Thus, any suitable number oftime periods and durations may be employed.

FIG. 2B shows the PRS muting cycle 200 of FIG. 2A as well as cellulartransmitter assignments within the PRS muting cycle 200, referred to as“cells” in the Figure. As can be seen 16 different cells arerepresented, with each assigned to one of the 8 time periods. Further,each time period may be assigned to multiple individual cells. Forexample, time period 1 is assigned to cells 8 and 14. As each new timeperiod arrives, the assigned cells broadcast their respective PRS forthe duration of the time period, which mobile devices can then receive.

When the last time period of the then-current PRS muting cycle 200 ends,the next PRS muting cycle begins. As can be seen in FIG. 2B, after timeperiod 8 of PRS muting cycle 200, time period 1 of the next PRS mutingcycle begins and cells 8 and 14 again broadcast their respective PRS.With knowledge of a PRS muting cycle and nearby cellular transmitter, amobile device can selectively wake-up and listen for PRS from individualcellular transmitters, thereby potentially saving power over examplesthat simply listen to all available PRS time periods within a PRS mutingcycle.

In instances where less-accurate position information is adequate, todetermine which PRS broadcasts to receive, the mobile device 110 mayobtain measurements about the quality of various available PRS withinthe PRS muting cycle at the mobile device's location, referred to as aPRS evaluation scan. The mobile device may perform these measurementsperiodically, e.g., every 5 minutes, or after a particular event occurs,such as a handoff to a new cellular transmitter or after the mobiledevice powers-on and boots. The quality of the received PRS may bedetermined and used to assign scores or ranks to one correspondingcellular transmitters or may be used to eliminate one or more cellulartransmitters from consideration for a period of time, e.g., until thenext PRS evaluation scan.

After determining the respective quality of each received PRS, themobile device 110 may then determine how many PRSs are appropriate for agiven position accuracy, select cellular transmitters having acceptablePRS quality, and select one or more time periods during which to wake upand receive PRS from the selected cellular transmitters. In someexamples, as will be discussed in more detail below, the mobile device110 may select the N cellular transmitters having the highest measuredPRS quality, where N is a number of PRS associated with a requestedposition accuracy. In other examples, however, the mobile device 110 mayselect cellular transmitters having high-quality PRS, but that tend tooverlap in the same time periods, which may reduce the number of timeperiods during which the mobile device 110 must wake up.

In some examples, rather than measuring PRS quality, the mobile devicemay receive PRS assistance data that includes PRS quality informationbased on the mobile device's estimated position, e.g., based on thecellular transmitter it is communicating with or a location provided bythe mobile device. The assistance data, in some examples, may include anidentification of cellular transmitters broadcasting PRS during a PRSmuting cycle, time periods within the PRS muting cycle associated withone or more of the cellular transmitters, quality information associatedwith one or more of the cellular transmitters, as well as informationabout the PRS muting cycle, e.g., a number of time periods and aduration of each time period.

In an example where the mobile device 110 receives PRS assistance datafrom an assistance server, the mobile device 110 may accept the PRSassistance data and select cellular transmitters based on the receivedPRS assistance data. In some examples, however, the mobile device 110may perform a PRS evaluation scan and provide the results of the PRSevaluation scan to the assistance server.

Referring now to FIG. 3, FIG. 3 shows an example system 300 for adaptivewake-up scheduling under PRS muting. The system 300 includes a PRSassistance system 310, which is in communication with a mobile device340 via a network 320, a base station 330, e.g., an eNodeB in an LTEnetwork, and a cellular transmitter 332. The PRS assistance system 310,which includes one or more servers 312 in communication with one or moredata stores 314 in this example, and is configured to receive requestsfor PRS assistance data from the mobile device 340 and to respond to therequests with PRS assistance data. In some examples, however, the PRSassistance system 310 may provide unsolicited PRS assistance data to themobile device 340, e.g., when the mobile device 340 powers-up andconnects to a cellular network, after handoff to a new eNodeB, etc.

In some examples, PRS assistance data provided by the PRS assistancesystem 310 may be crowdsourced. For example, mobile devices operated bycustomers of a cellular network provider may provide PRS measurementinformation and associated location information to the PRS assistancesystem 310. The PRS assistance system 310 may then catalog and store thePRS measurement information in the data store, e.g., in a relational orobject-oriented database, in a way that it is associated with thelocation information. At a later time, server(s) 312 of the PRSassistance system 310 may query the data store(s) 314 by providing alocation for which PRS assistance data is requested. The data store(s)314 may respond with one or more database records having PRS measurementinformation associated with the provided location.

In some examples, the PRS assistance system 310 may store eachnewly-received report of PRS measurement information in the datastore(s) 314 as a new record. In one such example system, each newrecord is associated with a time stamp and the PRS assistance system 310periodically purges data records older than a threshold age. Forexample, the PRS assistance system 310 may purge data records older than30 days or 6 months. However, in some examples, rather than storing eachnew record, new measurement data may be integrated with existingmeasurement data. Integrating new measurements with existing measurementdata may involve averaging the existing data with the new measurements,such as a weighted average, or may involve maintaining a history of themost recent N measurements, deleting the oldest of those measurements,and computing a new average with the prior N-1 measurement data and thenew measurement data. Still further examples for incorporating new PRSmeasurement information into the data store(s) 314 may be employedaccording to this disclosure.

In this example, the PRS assistance system 310 provides PRS assistancedata to the mobile device 340 that is not based on crowdsourcedinformation, but instead includes identities of cellular transmitters,respective assignments within a PRS muting cycle, and information aboutthe time periods within the PRS muting cycle, e.g., durations and numberof time periods. Further, the PRS assistance system 310, in someexamples, may provide other information, such as specific assignments ofcellular transmitters or time periods to use for location determinationat varying levels of precision.

For example, the PRS assistance system 310 may provide PRS assistancedata that identifies the number and identities of cellular transmittersto use for low accuracy, medium accuracy, high accuracy, and highestaccuracy location determinations. In one example, the PRS assistancedata may identify three cellular transmitters to use for low accuracylocation determination, five cellular transmitters to use for mediumaccuracy location determination, twelve cellular transmitters to use forhigh-accuracy location determination, and sixteen cellular transmittersto use for highest-accuracy location determination. The mobile device340 may then, based on a given or requested level of accuracy, selectthe corresponding cellular transmitters based on the received PRSassistance data. And while four levels of accuracy are described above,any suitable number of accuracy levels may be employed as well as anysuitable number of cellular transmitters per accuracy level may beemployed in different examples.

Further, while the examples above discuss location accuracy targets, thePRS assistance data may provide the number and identities of cellulartransmitters to use based on a desired rate of power consumption duringlocation determination using PRS. For example, the PRS assistance datamay include numbers and identities of cellular transmitters to use forlow power consumption, medium power consumption, high power consumption,and highest power consumption. Further, the PRS assistance data mayinclude two different sets of information—one related to locationaccuracy and one related to rates of power consumption. Thus, dependingon a power or accuracy target at the mobile device 400, the mobiledevice 400 may select one or more of the sets of information providedwithin the PRS assistance data.

For example, if a configuration or target for low power consumption isdetected, despite a need for high location accuracy, the mobile device400 may ignore the power consumption configuration in favor of locationaccuracy. Alternatively, the mobile device 400 may reduce a locationaccuracy below the requested location accuracy. Or in some examples,e.g., in an emergency scenario, the mobile device 400 may override apower consumption configuration in favor of obtaining thehighest-positional accuracy. To make such determinations, the mobiledevice 400 may be configured with one or more rules to resolve conflictsbetween power consumption configurations and location accuracy. In someexamples, the mobile device 400 may select a location accuracy havingthe fewest number of time periods during which to wake up, or the mobiledevice may select the location accuracy having the greatest number oftime periods during which to wake up. In some examples, the mobiledevice may select an intermediate number of time periods during which towake up. For example, if a power consumption configuration of the lowestpower configuration is received along with a high degree of locationaccuracy, the mobile device 400 may select a number of cellulartransmitters associated with a medium degree of location accuracy. Stillfurther variations may be employed according to other examples.

Referring now to FIG. 4, FIG. 4 shows an example mobile wireless device400 suitable for adaptive wake-up scheduling under PRS muting. In theexample shown in FIG. 4, the mobile device includes a processor 410, amemory 420, a wireless transceiver 412, a Global Navigation SatelliteSystem (“GNSS”) 414, such as a Global Positioning System (“GPS”)receiver, a display 430, a user input module 440, and a bus 450. In thisexample, the mobile device 400 is a cellular smartphone, but may be anysuitable device, include a cellular phone, a laptop computer, a tablet,a phablet, a personal digital assistant (“PDA”), wearable device, oraugmented reality device. The processor 410 employs bus 450 to executeprogram code stored in memory 420, to output display signals to adisplay 430, and to receive input from the user input module 440. Inaddition, the processor 410 is configured to receive information fromthe GPS receiver 414 and wireless transceiver 412 and to transmitinformation to the wireless transceiver 412.

The wireless transceiver 412 is configured to transmit and receivewireless signals via antenna 442 using link 444. For example, thewireless transceiver may be configured to communicate with a cellularbase station by transmitting signals to and receiving signals from anantenna associated with the cellular base station. In addition, thetransceiver 412 can receive PRS broadcast by one or more cellulartransmitters and provide information about each received PRS to theprocessor 410 to be used for OTDOA or other location techniques.

The GPS receiver 414 receives signals from one or more GPS satellitesand to provide location signals to the processor 410. And while thisexample employs a GPS receiver, any suitable GNSS receiver or receiversmay be employed in different examples. Further, it should be appreciatedthat various implementation options may be available in accordance withspecific power or accuracy targets in various applications. For example,a customized hardware in the same wafer or die of the silicon sensormight also be used, or particular elements might be implemented incustomized hardware, software or both, to replace the processor in theFIG. 4.

Referring now to FIG. 5, FIG. 5 shows an example method 500 for adaptivewake-up scheduling under PRS muting. The description of the examplemethod 500 below will be made with reference to the mobile device shownin FIG. 4 and the PRS muting cycle 200 shown in FIG. 2; however, itshould be understood that any suitable environment, PRS muting cycle, ormobile device may be employed according to different examples.

At block 510, the mobile device 110 receives, during one or moreevaluation time periods within a muting pattern cycle 200, referencesignals detectable by the mobile device 400 during the one or moreevaluation time periods within the muting pattern cycle. In thisexample, the mobile device 400 performs a PRS evaluation scan by wakingup and receiving PRS broadcast from cellular transmitters during eachtime period of the PRS muting cycle 200. In this example, the mobiledevice 400 stays “awake” during all time periods of a single PRS mutingcycle 200, thereby more quickly obtaining PRS measurements for eachcellular transmitter detectable by the mobile device 400. The cellulartransmitters, in this example, transmit 3GPP LTE PRS; however, in someexamples, other types of PRS may be transmitted.

However, in some examples of performing block 510, the mobile device 400may only wake up for a subset of the time periods of any iteration ofthe PRS muting cycle 200. For example, the mobile device 400 may wake upduring time periods 1 and 4 of a first iteration of the PRS muting cycle200, then during time periods 2 and 5 of the next iteration, and soforth, until PRS on all time periods have been received.

After receiving the PRS signals, the mobile device 400 performsmeasurements based on the received PRS. In this example, the mobiledevice performs Reference Signal Time Difference (“RTSD”) measurementsaccording to 3GPP Technical Specification (“TS”) 36.214 to perform OTDOApositioning; however, in other examples, other measurement techniquesmay be employed. In this example, the RTSD indicates a relative timingdifference between two cells, a reference cell and the measured cell,based on the smallest time difference between two subframe boundariesreceived from the two different cells.

In some examples, the mobile device 400 may perform multiple evaluationscans or perform multiple measurements of each time period of the PRSmuting cycle. Such measurements may be performed on consecutiveiterations of a PRS muting cycle, or may be performed periodically overtime. For example, the mobile device 400 may measure PRS every 5minutes, or after an event, such as handover to a new cellulartransmitter or after the mobile device is first powered on, afterawaking from a sleep mode, or following a loss of signal from a GNSSsatellite.

In some examples, the mobile device 400 may return to block 510periodically based on a detected movement of the mobile device 400. Forexample, the mobile device 400 may receive sensor signals, e.g., from anaccelerometer, indicating movement of the mobile device 400. From suchsensor signals, the mobile device 400 may estimate a speed or velocityof the mobile device 400, e.g., based on a walking speed or stridelength of the user of the mobile device 400, and after a referencedistance has been travelled, the mobile device 400 may perform a new PRSevaluation scan at block 510. For example, the reference distance canindicate that the signaling environment for the mobile device 400 haschanged significantly and that new evaluation of the signals receivedaccording to the muting pattern cycle is appropriate. Hence, thereceiving, by the mobile device 400 reference signals, and subsequentmeasurement of the received signals, during the one or more evaluationtime periods discussed above may be repeated as appropriate. Means forperforming the functions described above with reference to block 510include, for example, the processor 410 and the wireless transceiver412. In some examples, the processor 410 may executeprocessor-executable instructions stored in memory 420 to activate thewireless transceiver 412 at a time corresponding to one or more PRSsignals and configure the wireless transceiver 412 to receive such oneor more PRS signals using the antenna 442. The processor 410 may thenreceive information from the transceiver corresponding to one or morereceived PRS signals

At block 520, the mobile device 400 optionally determines a power oraccuracy target for a location determination. In one example, anapplication executing on the mobile device 400 transmits a request for alocation to a location service executed by the mobile device 400. Inthis example, the request includes an indication of an accuracy targetfor the location. An indication of an accuracy target may be anacceptable error in a location, e.g., within 20 meters, or may be arelative accuracy target. For example, the location service executed bythe mobile device may define one or more levels of accuracy availablefor a location request, such as low accuracy, medium accuracy, highaccuracy, and highest accuracy. Thus, a request from the application mayindicate one of the levels of accuracy.

In some examples, the application may not provide an indication of anaccuracy target, but may instead infer an accuracy target. For example,a mobile device may associate a maximum accuracy target with a requestreceived from an emergency service, such as a designated emergency phonenumber (e.g., 911 or 999). In contrast, a location request from a socialmedia application, e.g., Facebook or Instagram, may be associated with alow accuracy target. Similarly, a location request from a navigationapplication may be associated with a high accuracy target.

As discussed above, a mobile device may determine a power consumptiontarget associated with a location request. Such a power consumptiontarget may be based on a current battery level or current powerconsumption rate by the mobile device. In some examples, however, thepower consumption target may be associated with a volume of locationrequests received from an application over time. For example, a socialmedia application may issue location requests at a relatively shortinterval, e.g., every minute, which may result in significant powerconsumption if the mobile device were to wake up for each time period ina PRS muting cycle. Thus, the mobile device 400 may determine a powerconsumption target based on a volume of requests. Further, in someexamples, an application may provide an explicit indication of a powerconsumption target for a location determination. Means for performingthe functions described above with reference to block 520 include, forexample, the processor 410, which may execute processor-executableinstructions stored in memory 420 to access one or more configurations,e.g., from a memory 420 or a configuration file.

At block 530, the mobile device 400 may determine a subset of timeperiods within the PRS muting cycle. The subset that is determined canthen be used for measuring reference signals to compute a location forthe mobile device 400. By use of the term “subset,” it is understoodthat the subset of the muting pattern cycle comprises a number of timeperiods that is fewer than the two or more time periods of the mutingpattern cycle. In one example, the subset of time periods within the PRSmuting cycle is determined based on a quality of the measured referencesignals. In this example, the mobile device 400 ranks the detectedcellular transmitters based on a corresponding quality of the receivedPRS from the respective cellular transmitter. In some examples, themobile device 400 may also eliminate from consideration any cellulartransmitter below a reference quality threshold. Although block 520 isshown occurring before block 530 for this example, it is understood thatblock 530 may occur before block 520.

In this example, the mobile device 400 maintains a data structure, e.g.,a table, correlating a number of time periods with a location accuracyor a power consumption. For example, as discussed above, the correlationmay indicate two cellular transmitters to use for low accuracy locationdetermination, four cellular transmitters to use for medium accuracylocation determination, twelve cellular transmitters to use forhigh-accuracy location determination, and sixteen cellular transmittersto use for highest-accuracy location determination.

In some examples, after determining a location accuracy or powerconsumption target, the mobile device 400 selects a number of timeperiods of the PRS muting cycle during which to wake up and receive PRSsignals. As discussed above, a number of time periods may be maintainedin a data structure, thus the mobile device may access the datastructure to determine the number of time periods. The mobile device maythen select one or more time periods based on the quality of themeasured reference signals. For example, after selecting a number oftime periods, e.g., N time periods time periods, based on the locationaccuracy target or the power consumption target, the mobile device 400may then determine the subset of the muting pattern cycle for measuringreference signals, for example, the N cellular transmitters with thehighest quality measurements, irrespective of overlap within particulartime periods. Hence, in implementations where the number of time periodsto measure is determined first, the subset of the muting pattern cyclecan be determined, at least in part, on the number and on anotherfactor, such as the quality of measurements associated with the subset.However, in some examples, the mobile device 400 may select cellulartransmitters to minimize the number of time periods during which towake.

In one example, the mobile device 400 determines that four PRSmeasurements are to be performed for a location accuracy target. Themobile device 400 may then select a time period in the PRS muting cycle200 corresponding to the cellular transmitter having highest-qualityPRS. The mobile device 400 may then search for additional nearbycellular transmitters also transmitting PRS during the selected timeperiod. If one or more is discovered, the mobile device 400 may alsoidentify one or more of those discovered cellular transmitters ascandidates from which to obtain PRS measurements. Thus, the mobiledevice 400 may select multiple cellular transmitters from which toconcurrently receive PRS or it may receive multiple PRS from a singlecellular transmitter (or even multiple cellular transmitters) overmultiple time periods. The mobile device 400 proceeds accordingly untila number of cellular transmitters and time periods has been selectedduring which the mobile device 400 wake up and listen for PRS.

In some examples, however, the mobile device 400 may select time periodsbased on parameters other than, or in addition to, a quality metric.Selecting PRS sources in directions covering a wider arc around themobile device 400 may provide more useful information to determine themobile device's location than three high quality PRS sources that aregenerally in the same direction from the mobile device 400.

For example, referring to FIG. 1, if PRS sources 120 c-e have thehighest quality scores of the available PRS sources, the mobile device110 may nevertheless select PRS sources 120 c, 120 e, and 120 h, wherePRS source 120 h has a lower quality score, but is located at ageographically diverse location from PRS sources 120 c, 120 d which arelocated along approximately the same vector from the mobile device 110.Such geographical diversity may provide more useful information whendetermining the mobile device's location in some examples.

To determine one or more PRS sources based on geographical diversity,the mobile device 400 may determine a direction to each of one or morePRS source candidates based on an accuracy or location target. Themobile device 400 may then select a highest-quality PRS source and thendetermine a score for the next N highest-quality PRS sources and weighteach of the sources based on geographic diversity from the selectedhighest-quality PRS source. Such weighting may be based on an anglebetween a direction to the selected highest-quality PRS source and arespective one of the next N highest-quality PRS sources.

A preferred geographic diversity may vary based on a number of PRSsources to be measured based on a location accuracy or power consumptiontarget. For example if a location accuracy or power consumption targetindicates three PRS sources are to be used, a preferred geographicdiversity may include three PRS sources equally spaced around the mobiledevice 400 at angles of 120 degrees from the adjacent PRS sources. In acase where six PRS sources are to be used, a preferred geographicdiversity may include PRS sources equally spaced around the mobiledevice 400 at angles of 60 degrees from the adjacent PRS sources. Whilesuch exact spacing may not be available in all scenarios, a mobiledevice 400 may select one or more PRS sources to approximate suchgeographic diversity parameters. It should be appreciated, however, thatother geographic diversity parameters may be employed in differentexamples. As shown in the examples above, when determining a subset ofthe muting pattern cycle for measuring reference signals, the mobiledevice may make such a determination based on a quality of the measuredreference signals, a geographic diversity of candidate reference signalsources, a power consumption target, a location accuracy target, or anycombination thereof. Means for performing the functions described abovewith reference to block 530 include the processor 410 of the mobiledevice 400 executing processor-executable instructions stored in memory420 to perform the function(s) discussed above with respect to block530.

At block 540, the mobile device 400 receives and measures referencesignals only during the time periods of the subset of the muting patterncycle determined in block 530. In one example, the mobile device 400wakes up during the selected time periods of the PRS muting cycle 200,receives PRS from one or more cellular transmitters, and sleeps (therebynot receiving PRS) during non-selected time periods. As discussed above,by only waking up during certain time periods, and sleeping through theothers, the mobile device 400 is able to reduce its power consumptionwhile still obtaining enough information for determining its locationwithin the accuracy targets of a particular application. In one example,the mobile device 400 performs measurements on the received PRS, such asperforming RTSD measurements as described above. Means for performingthe functions described above with reference to block 540 include thewireless transceiver 412 or the processor 410 of the mobile device shownin FIG. 4. For example, the processor 410 may executeprocessor-executable instructions stored in memory 420 to enable thewireless transceiver 412 to receive PRS from one or more cellulartransmitters using antenna 442. The wireless transceiver 412 may thenreceive such PRS and provide to the processor 410 information related tothe received signals. In some examples, the wireless transceiver 412 mayperform one or more of the measurements of the received PRS, or mayprovide information to the processor 410 to enable the processor 410 toperform one or more measurements of the received PRS.

At block 550, after performing the measurements, the mobile device 400location is determined based on the reference signals measured duringthe determined subset of the muting pattern cycle. In one example, themobile device 400 transmits them to a remote device (which is configuredto determine a location of the mobile device based on the referencesignals measured during the determined subset of the muting patterncycle), such as a cellular network device, which determines the mobiledevice's location based on the measurements, and transmits thedetermined location back to the mobile device 400. In some examples,however, rather than transmitting the measured received signals to aremote device, the mobile device 400 determines its location based onthe measurements. Means for performing the functions described abovewith reference to block 550 include the processor 410 of the mobiledevice 400 shown in FIG. 4, or may include, for example, one or morecomponents of the PRS assistance system 310 shown in FIG. 3, such as oneor more servers 312, executing processor-executable instructions storedin memory 420 to perform the function(s) discussed above with respect toblock 550.

It should be appreciated that while the steps of the method 500 shown inFIG. 5 are illustrated and described in a particular order, noparticular order is required. For example, block 520 may be performedbefore block 510. Still further variations of the orderings of themethod 500 are contemplated within the scope of this disclosure.

Referring now to FIG. 6, FIG. 6 shows an example method 600 for adaptivewake-up scheduling under PRS muting. The description of the examplemethod 600 below will be made with reference to the mobile device shownin FIG. 4 and the PRS muting cycle 200 shown in FIG. 2; however, itshould be understood that any suitable environment, PRS muting cycle, ormobile device may be employed according to different examples.

At block 610, the mobile device 400 receives one or more referencesignal measurement configurations for a muting pattern cycle. In thisexample, the mobile device 400 receives a configuration from a PRSassistance system 310 that includes information regarding available PRS,corresponding time periods, and qualities of one or more of the PRS. Itis understood that the configuration can be geographically dependent andthat based on the rough location of the mobile device 400 at any giventime, the reference signal measurement configuration(s) can change. Thereference signal measurement configuration(s) can therefore be updatedwhen the mobile device 400 is in a different location. For example,referring to the PRS muting cycle 200 shown in FIGS. 2A and 2B, theconfiguration includes the following, where ‘Quality’ has value rangingfrom 0 (worst) to 10 (best):

TABLE 1 PRS Time Source Period Quality 1 5 9 2 2 10 3 6 3 4 3 2 5 4 6 66 1 7 2 6 8 1 7 9 4 4 10 7 9 11 2 8 12 6 3 13 8 4 14 1 5 15 5 2 16 8 3

Such configuration information may enable the mobile device 400 to usethe configuration information rather than perform a PRS evaluation scan,thereby reducing power consumption associated with PRS evaluation scans.At a later time when selecting one or more PRS sources to receive (by,for example, awakening from a standby or sleep mode in order to receive)and measure, the mobile device 400 can access the data structure and,based on an accuracy or power consumption target, select appropriate PRSsources. While the example shown above includes a “quality” metric,other examples may include other or additional metrics, such as apriority metric, a direction vector from a location to the PRS signalsource (to allow for selecting a subset of the muting pattern cyclebased on geographic diversity, for example), a distance to the PRSsignal source (possibly for geographic diversity or other reasons, forexample), or others. Such information may be employed by the mobiledevice 400 when selecting one or more PRS sources to measure as will bedescribed in more detail below.

In some examples, a priority (or priority metric) of a time period maybe modified by the mobile device. For example, if while attempting toreceive PRS during a time period, the mobile does not detect PRS, themobile device may determine that no detectable PRS signal is availablein that time period, and reduce a priority of the time period, e.g., bysetting it to a minimum value or by decrementing an associated priority.In some examples, the mobile device may instead, detect one or morestrong PRS during a time period and may increase a priority of the timeperiod, which may allow the time period to be selected in favor ofanother time period. And while, in some examples, a priority for a timeperiod may be reduced or increased during a particular evaluation scan,or while the mobile device is determining its location, such a change inpriority may be temporary. For example, a changed priority may bemaintained for a predetermined period of time, or only while the mobiledevice is within a particular area. Further, in some examples, when amobile device is performing an evaluation scan, it may reset prioritiesfor time periods prior to the evaluation scan.

In some examples, reference signal measurement configurations mayinstead include multiple configurations, each associated with anaccuracy or power consumption target. For example, the PRS assistancesystem 310 may transmit separate reference signal measurementconfigurations for different accuracy or power consumption target. Forexample, the PRS assistance system 310 may transmit four separatereference signal measurement configurations, one each corresponding tofour different accuracy targets: (1) low accuracy (e.g., 30-50 meters(m)), (2) moderate accuracy (20-30 m), (3) high accuracy (10-20 m), and(4) highest accuracy (<10 m). Each configuration may include PRS sourcesto use and corresponding time periods.

In some examples, the PRS assistance system 310 may transmit referencesignal measurement configurations based on power consumption targetsrather than accuracy targets, or each configuration may be applicable toboth a corresponding accuracy and power consumption target. For example,the PRS assistance system 310 may transmit four configurations, one eachfor levels corresponding to low, moderate, high, and highest, with eachlevel equally-applicable to power consumption and location accuracy. Insome examples, however, different numbers or types of configurations maybe provided for location accuracy or power consumption, or one or moreconfigurations may be provided corresponding to power consumption andlocation accuracy, e.g., low power, moderate accuracy.

In some examples, the PRS assistance system 310 may transmit multipletypes of reference signal measurement configurations. For example, thePRS assistance system 310 may send reference signal measurementconfigurations both for accuracy and power. Further, in some examples,may send multiple configurations for each of the types. For example, thePRS assistance system 310 may send up to four reference signalmeasurement configurations each for accuracy and power. In someexamples, the PRS assistance system 310 may send a configuration foreither or both of high accuracy or high power and a configuration foreither or both of a low accuracy or low power. One such example mayenable a mobile device to select an appropriate reference signalmeasurement configuration based on one or more targets for accuracy orpower.

While the examples above relate to selecting PRS sources, in someexamples, a reference signal measurement configurations may compriseinformation indicating which time periods during which to receive andmeasure PRS. Referring to FIG. 7, FIG. 7 illustrates a graphicalrepresentation of a reference signal measurement configuration thatspecifies time periods during which to receive PRS—indicated by an “X”in the respective time period— and time periods during which to remainidle. In this example, the reference signal measurement configurationindicates that PRS is to be received during time periods 1, 4, and 5only; however, it should be appreciated that any combination of timeperiods may be specified in a reference signal measurementconfiguration. Further, as discussed above, a mobile device 400 mayreceive multiple reference signal measurement configurations indicatingdifferent time periods during which to receive PRS, such as based ondiffering location accuracy or power consumption targets.

In some examples, a reference signal measurement configurations maycomprise a bit field indicating which time periods of a PRS muting cycleduring which to receive PRS. For example, the 8 least-significant bitsof a bit field corresponding to the reference signal measurementconfiguration of FIG. 7 may comprise 0×00011001, where time period 1 isrepresented at bit position 0. It should be appreciated that the widthof a bit field may vary based on the number of time periods within a PRSmuting cycle. Means for performing the functions described above withreference to block 610 include X, Y, and/or Z.

At block 620, the mobile device 400 optionally determines a powerconsumption or accuracy target generally as discussed above with respectto block 520. Means for performing the functions described above withreference to block 620 include, for example, the processor 410 and thewireless transceiver 412. In some examples, the processor 410 mayexecute processor-executable instructions stored in memory 420 toactivate the wireless transceiver 412 at a time corresponding to one ormore PRS signals and configure the wireless transceiver 412 to receivesuch one or more PRS signals using the antenna 442. The processor 410may then receive information from the transceiver 412 corresponding toone or more received PRS signals.

At block 630, the mobile device 400 selects a reference signalmeasurement configuration based on the determined power consumption oraccuracy target. In this example, the mobile device 400 selects andaccesses the reference signal measurement configuration shown in Table 1and discussed above with respect to block 610. In addition, optionally,the mobile device 400 uses the determined power consumption or accuracytarget to select one or more PRS sources from the configuration. Forexample, a moderate accuracy target may indicate that 6 PRS sourcesshould be measured. The mobile device 400 may then select 6 PRS sourcesfrom the configuration.

In this example, the mobile device 400 selects the PRS sources havingthe 6 highest quality scores, which are, in order, PRS sources 2, 1, 10,11, 8, and 7. In some examples, the mobile device 400 may select PRSsources based on quality or other metrics. For example, the mobiledevice 400 may select one or more PRS sources based on quality and adirection to the respective PRS source, such as the geographicaldiversity metric described above with respect to block 530 of FIG. 5.

While in this example, a reference signal measurement configuration isreceived from the PRS assistance system 310, measurement configurationsmay be generated by the mobile device 400 itself. Hence, a referencesignal measurement configuration may be obtained either by the mobiledevice itself, as shown, for example, in the method 500 of FIG. 5 whichincludes performing a PRS evaluation scan, which may provide informationregarding PRS sources. The mobile device may then select a measurementconfiguration based on the results of the PRS evaluation scan, or mayupdate the quality parameters within the received reference signalmeasurement configuration based on the results of the PRS evaluationscan. In some examples, the mobile device 400 may also transmit theresults of the PRS evaluation scan to the PRS assistance system 310 toenable it to update its assistance information. Hence, the signalmeasurement configurations generated by the server for sending to mobiledevices can be, in one example, crowdsourced from information receivedfrom a plurality of mobile devices. Means for performing the functionsdescribed above with reference to block 630 include the processor 410 ofthe mobile device 400 shown in FIG. 4 executing processor-executableinstructions stored in memory 420 to perform the function(s) discussedabove with respect to block 630.

At block 640, the mobile device 400 measures reference signals onlyduring the subset of the muting pattern cycle, where the subset of themuting pattern cycle is selected or determined based on the receivedsignal measurement configuration, as discussed above with respect toblock 540 of FIG. 5. Means for performing the functions described abovewith reference to block 640 include the wireless transceiver 412 or theprocessor 410 of the mobile device shown in FIG. 4. For example, theprocessor 410 may execute processor-executable instructions to enablethe wireless transceiver 412 to receive PRS from one or more cellulartransmitters. The wireless transceiver 412 may then receive such PRS andprovide to the processor 410 information related to the receivedsignals. In some examples, the wireless transceiver 412 may perform oneor more of the measurements of the received PRS, or may provideinformation to the processor 410 to enable the processor 410 to performone or more measurements of the received PRS.

It should be appreciated that while the steps of the method 600 shown inFIG. 6 are illustrated and described in a particular order, noparticular order is required. For example, block 620 may be performedbefore block 610. Further, block 630 may be performed prior to blocks610 or 620, e.g., based on a default configuration or a previouslyreceived measurement configuration. Still further variations of theorderings of the method 500 are contemplated within the scope of thisdisclosure.

It should also be appreciated that aspects of the method 500 of FIG. 5may be incorporated into the method 600 of FIG. 6, or aspects of themethod 500 of FIG. 6 may be incorporated into the method 600 of FIG. 5.For example, a mobile device 400 may perform the method 600 of FIG. 6,but may also perform a PRS evaluation scan. Such a scan may be employedto verify or correct information received from the PRS assistance system310, or to provide feedback information to the PRS assistance system.

While the methods and systems herein are described in terms of softwareexecuting on various machines, the methods and systems may also beimplemented as specifically-configured hardware, such asfield-programmable gate array (FPGA) specifically to execute the variousmethods. For example, examples can be implemented in digital electroniccircuitry, or in computer hardware, firmware, software, or in acombination thereof. In one example, a device may include a processor orprocessors. The processor comprises a computer-readable medium, such asa random access memory (RAM) coupled to the processor. The processorexecutes computer-executable program instructions stored in memory, suchas executing one or more computer programs for adaptive wake-upscheduling under PRS muting. Such processors may comprise amicroprocessor, a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), field programmable gatearrays (FPGAs), and state machines. Such processors may further compriseprogrammable electronic devices such as PLCs, programmable interruptcontrollers (PICs), programmable logic devices (PLDs), programmableread-only memories (PROMs), electronically programmable read-onlymemories (EPROMs or EEPROMs), or other similar devices.

Such processors may comprise, or may be in communication with, media,for example computer-readable storage media, that may store instructionsthat, when executed by the processor, can cause the processor to performthe steps described herein as carried out, or assisted, by a processor.Examples of computer-readable media may include, but are not limited to,an electronic, optical, magnetic, or other storage device capable ofproviding a processor, such as the processor in a web server, withcomputer-readable instructions. Other examples of media comprise, butare not limited to, a floppy disk, CD-ROM, magnetic disk, memory chip,ROM, RAM, ASIC, configured processor, all optical media, all magnetictape or other magnetic media, or any other medium from which a computerprocessor can read. The processor, and the processing, described may bein one or more structures, and may be dispersed through one or morestructures. The processor may comprise code for carrying out one or moreof the methods (or parts of methods) described herein including, forexample, one or more block depicted in FIGS. 5 and 6.

The foregoing description of some examples has been presented only forthe purpose of illustration and description and is not intended to beexhaustive or to limit the disclosure to the precise forms disclosed.Numerous modifications and adaptations thereof will be apparent to thoseskilled in the art without departing from the spirit and scope of thedisclosure.

Reference herein to an example or implementation means that a particularfeature, structure, operation, or other characteristic described inconnection with the example may be included in at least oneimplementation of the disclosure. The disclosure is not restricted tothe particular examples or implementations described as such. Theappearance of the phrases “in one example,” “in an example,” “in oneimplementation,” or “in an implementation,” or variations of the same invarious places in the specification does not necessarily refer to thesame example or implementation. Any particular feature, structure,operation, or other characteristic described in this specification inrelation to one example or implementation may be combined with otherfeatures, structures, operations, or other characteristics described inrespect of any other example or implementation.

Use herein of the word “or” is intended to cover inclusive and exclusiveOR conditions. In other words, A or B or C includes any or all of thefollowing alternative combinations as appropriate for a particularusage: A alone; B alone; C alone; A and B only; A and C only; B and Conly; and A and B and C.

What is claimed is:
 1. A method for measuring, by a mobile device, aplurality of reference signals for positioning having a muting patterncycle comprising two or more time periods, the method comprising:receiving, by the mobile device, a reference signal measurementconfiguration for the muting pattern cycle from a server; and measuring,by the mobile device, reference signals only during a subset of the twoor more time periods of the muting pattern cycle based on the referencesignal measurement configuration.
 2. The method of claim 1, wherein thereceiving the reference signal measurement configuration comprisesreceiving one or more reference signal measurement configurations from aserver, the method further comprising determining a power consumptiontarget or a location accuracy target, and selecting the reference signalmeasurement configuration from the plurality of reference signalmeasurement configurations based at least in part on the powerconsumption target or the location accuracy target.
 3. The method ofclaim 1, wherein the obtaining the signal measurement configurationcomprises receiving a plurality of reference signal measurementconfigurations, the method further comprising selecting the referencesignal measurement configuration from the plurality of reference signalmeasurement configurations based at least in part on a geographicdiversity of candidate reference signal sources.
 4. The method of claim1, wherein the reference signal measurement configuration comprises aquality of a reference signal measurement associated with a signalsource.
 5. The method of claim 1, wherein the reference signalmeasurement configuration comprises a bit field corresponding to themuting pattern cycle, the bit field indicating one or more time periodsduring which to measure one or more of the reference signals.
 6. Themethod of claim 1, wherein the reference signal measurementconfiguration comprises a first reference signal measurementconfiguration and a second reference signal measurement configuration,the first reference signal measurement configuration associated with ahigh power or high accuracy, and the second measurement configurationassociated with a low power or low accuracy.
 7. The method of claim 1,further comprising, determining a location of the mobile device based onthe reference signals measured during the subset of the muting patterncycle.
 8. The method of claim 1, further comprising: transmitting one ormore of the references signals measured during the subset of the mutingpattern cycle to a remote device, the remote device configured todetermine a location of the mobile device based on the reference signalsmeasured during the subset of the muting pattern cycle; and receivingthe location of the mobile device.
 9. A device for measuring a pluralityof reference signals for positioning having a muting pattern cyclecomprising two or more time periods comprising: a non-transitorycomputer-readable medium storing processor-executable instructions; aprocessor in communication with the non-transitory computer-readablemedium, the processor configured to execute the processor-executableprogram code to: receive a reference signal measurement configurationfor a muting pattern cycle from a server; and measure reference signalsonly during a subset of the muting pattern cycle based on the referencesignal measurement configuration.
 10. The device of claim 9, whereinprocessor-executable program code is further configured to cause theprocessor to: receive one or more reference signal measurementconfigurations from a server, determine a power consumption target or alocation accuracy target for a location measurement, and select thereference signal measurement configuration from the plurality ofreference signal measurement configurations based at least in part onthe power consumption target or the location accuracy target.
 11. Thedevice of claim 9, wherein processor-executable program code is furtherconfigured to cause the processor to: receive one or more referencesignal measurement configurations from a server, and select thereference signal measurement configuration from the plurality ofreference signal measurement configurations based at least in part on ageographic diversity of candidate reference signal sources.
 12. Thedevice of claim 9, wherein the reference signal measurementconfiguration comprises a quality of a reference signal measurementassociated with a signal source.
 13. The device of claim 9, wherein thereference signal measurement configuration comprises a bit fieldcorresponding to the muting pattern cycle, the bit field indicating oneor more time periods during which to measure one or more of thereference signals.
 14. The device of claim 9, wherein the referencesignal measurement configuration comprises a first reference signalmeasurement configuration and a second reference signal measurementconfiguration, the first reference signal measurement configurationassociated with a high power or high accuracy target, and the secondreference signal measurement configuration associated with a low poweror low accuracy target.
 15. The device of claim 9, whereinprocessor-executable program code is further configured to cause theprocessor to determine a location of the mobile device based on thereference signals measured during the subset of the muting patterncycle.
 16. A non-transitory computer-readable medium storingprocessor-executable instructions configured to cause a processor to:receive a reference signal measurement configuration for a mutingpattern cycle from a server; and measure reference signals only during asubset of the muting pattern cycle based on the reference signalmeasurement configuration.
 17. The non-transitory computer-readablemedium of claim 16, wherein processor-executable program code is furtherconfigured to cause the processor to: receive one or more referencesignal measurement configurations from a server, determine a powerconsumption target or a location accuracy target for a locationmeasurement, receive a plurality of a reference signal measurementconfigurations, and select the reference signal measurementconfiguration from the plurality of reference signal measurementconfigurations based at least in part on the power consumption target orthe location accuracy target.
 18. The non-transitory computer-readablemedium of claim 16, wherein processor-executable program code is furtherconfigured to cause the processor to: receive one or more referencesignal measurement configurations from a server, and select thereference signal measurement configuration from the plurality ofreference signal measurement configurations based at least in part on ageographic diversity of candidate reference signal sources.
 19. Thenon-transitory computer-readable medium of claim 16, wherein thereference signal measurement configuration comprises a quality of areference signal measurement associated with a signal source.
 20. Thenon-transitory computer-readable medium of claim 16, wherein thereference signal measurement configuration comprises a bit fieldcorresponding to the muting pattern cycle, the bit field indicating oneor more time periods during which to measure one or more of thereference signals.
 21. The non-transitory computer-readable medium ofclaim 16, wherein the reference signal measurement configurationcomprises a first reference signal measurement configuration and asecond reference signal measurement configuration, the first referencesignal measurement configuration associated with a high power or highaccuracy target configuration, and the second reference signalmeasurement configuration associated with a low power or low accuracytarget.
 22. The non-transitory computer-readable medium of claim 16,wherein processor-executable program code is further configured to causethe processor to determine a location of the mobile device based on thereference signals measured during the subset of the muting patterncycle.
 23. An apparatus for measuring a plurality of reference signalsfor positioning having a muting pattern cycle comprising two or moretime periods, the apparatus comprising: means for receiving a referencesignal measurement configuration for the muting pattern cycle from aserver; and means for measuring reference signals only during a subsetof the muting pattern cycle based on the reference signal measurementconfiguration.
 24. The apparatus of claim 23, wherein the means forreceiving the reference signal measurement configuration comprises meansfor receiving one or more reference signal measurement configurationsfrom a server, and further comprising: means for determining a powerconsumption target or a location accuracy target for a locationmeasurement; and means for selecting the reference signal measurementconfiguration from the plurality of reference signal measurementconfigurations based at least in part on the power consumption target orthe location accuracy target.
 25. The apparatus of claim 23, wherein themeans for receiving the reference signal measurement configurationcomprises means for receiving one or more reference signal measurementconfigurations, and further comprising means for selecting a referencesignal measurement configuration from the plurality of reference signalmeasurement configurations based at least in part on a geographicdiversity of candidate reference signal sources.
 26. The apparatus ofclaim 23, wherein the reference signal measurement configurationcomprises a quality of a reference signal measurement associated with asignal source.
 27. The apparatus of claim 23, wherein the referencesignal measurement configuration comprises a bit field corresponding tothe muting pattern cycle, the bit field indicating one or more timeperiods during which to measure one or more of the reference signals.28. The apparatus of claim 23, wherein the reference signal measurementconfiguration comprises a first reference signal measurementconfiguration and a second reference signal measurement configuration,the first reference signal measurement configuration associated with ahigh power or high accuracy target, and the second reference signalmeasurement configuration associated with a low power or low accuracytarget.
 29. The apparatus of claim 23, further comprising: means fordetermining a location of the mobile device based on the referencesignals measured during the subset of the muting pattern cycle.